Phase Transformations in Multicomponent Melts

450 Pages·2008·6.69 MB·English

Phase Transformations
in Multicomponent Melts
Edited by
Dieter M. Herlach
Further Reading
Hirsch, J., Gottstein, G., Skrotzki, B. (eds.)
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2008
ISBN: 978-3-527-32367-8
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Phase Transformations
in Multicomponent Melts
Edited by
Dieter M. Herlach
The Editor All books published by Wiley-VCH are care-
fully produced. Nevertheless, authors, editors,
and publisher do not warrant the informa-
Prof. Dr. Dieter M. Herlach
tion contained in these books, including this
Deutsches Zentrum fu¨r Luft- und Raumfahrt
book, to be free of errors. Readers are ad-
(DLR)
vised to keep in mind that statements, data,
Institut fu¨r Materialphysik im Weltraum
illustrations, procedural details or other items
Linder Ho¨he
may inadvertently be inaccurate.
D-51147 Ko¨ln
Germany
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applied for
and
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www.dieter-herlach.de
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grafie; detailed bibliographic data are avail-
able on the Internet at <http://dnb.d-nb.de>.
The figure shows a dendrite in a slightly off-
eutectic AlAgCu alloy cast into a cold alu-
minium mould. The dendrite consists of two  2008 WILEY-VCH Verlag GmbH & Co.
KGaA, Weinheim
intermetallic phases (Al Cu and Ag Cu) and
2 2
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ISBN: 978-3-527-31994-7
V
Foreword
The traditional research field of phase transformations in liquid metals is of great
importance in materials production. It attracted new interest in research since the
development of novel methods of modeling such as the phase field approach, and
the application of new experimental techniques such as levitation processing to
directly observe phase transformations on freely suspended liquid samples. The
exciting progress in this field stimulated innovative work in describing microstruc-
ture evolution as a function of processing parameters even in multicomponent
alloys, which is a mandatory boundary condition for a predictive capability in
materials design.
The recent efforts have led to a multidisciplinary cooperation of mathemati-
cians, theoretical and experimental physicists, chemists, and materials scientists
of mechanical engineering. The Deutsche Forschungsgemeinschaft has essentially
enforced the interdisciplinary cooperation by approving a new priority programme
SPP1120 on Phase Transformations in Multicomponent Melts. The priority pro-
gramme was funded over six years and was found to be very successful at its
end.
More than 20 research groups from German universities and research cen-
ters were combined within the priority programme. Phase field models were
employed and extended for the description of solidification modes in Aachen,
Ju¨lich, Karlsruhe, Ko¨ln, Magdeburg, and Regensburg. These mesoscopic mod-
eling were complemented by microscopic modeling as molecular dynamics in
Go¨ttingen and Mainz, and modeling by a hard sphere system in Dresden. How-
ever, reliable modeling of phase transformations require careful measurements
of thermophysical parameters of selected sample systems that came from groups
in Berlin, Clausthal-Zellerfeld, Chemnitz, Ko¨ln, and Mu¨nchen. The priority pro-
gramme made it possible to directly verify the predictions of modeling with results
of experiments of growth dynamics and microstructure evolution, which were
performed in Aachen, Dresden, Go¨ttingen, and Ko¨ln. Even dedicated systems were
investigated as nanoscale systems in Karlsuhe, Mu¨nster, and Saarbru¨cken, which
play an essential role in the young research field of nanomaterials. Last but not
least, a complete new approach was started in the priority programme SPP1120 to
test colloidal systems as model systems for metals and alloys in Ko¨ln and Mainz.
Phase Transformations in Multicomponent Melts. Edited by D. M. Herlach
Copyright  2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
ISBN: 978-3-527-31994-7
VI Foreword
The latter activity has led to a new priority programme SPP1296 that is supported
by the Deutsche Forschungsgemeinschaft since 2007.
During the course of the running priority programme, it was very active in
reporting the results to the scientific community during national and international
conferences in Hamburg, Dresden, Regensburg, Lausanne, Mu¨nchen, and Prag.
Even presentations were realized to the public during exhibitions in Dresden. It is
also evident in many publications of referred scientific journals and many invited
talks of its members at international congresses. Not to forget its merit to educate
young scientists to establish a new generation of scientists in research and industry,
which is very important to hold and even increase the high standard of research in
the field of phase transformations from which our industrial society may benefit
in the future. During the six years of its existence new full chairs in materials
physics and science were occupied by young members of the priority programme
in Aachen, Bochum, Dresden, Karlsruhe, Ko¨ln, Leoben, and Mu¨nster.
The priority programme worked so well also thanks to the engagement of its
coordinator, Professor Dr Dieter Herlach from Ko¨ln, who did an excellent job. We
congratulate him and all the members of the priority programme for the enormous
outcome of this network.
Go¨ttingen, 30 June 2008 Professor Dr. Reiner Kirchheim
VII
Contents
Foreword V
Preface XVII
List of Contributors XXI
Part One Thermodynamics 1
1 Phase Formation in Multicomponent Monotectic Al-based Alloys 3
Joachim Gro¨bner, Djordje Mirkovic´, and Rainer Schmid-Fetzer
1.1 Introduction 3
1.2 Experimental Methods 4
1.3 Systematic Classification of Ternary Monotectic Phase Diagrams 4
1.4 Selected Ternary Monotectic Alloy Systems 6
1.4.1 Al–Bi–Zn: Type 2a Monotectic System 6
1.4.2 Al–Bi–Sn: Type 1b Monotectic System 6
1.4.3 Al–Sn–Cu: Type 3a Monotectic System 8
1.4.4 Al–Bi–Cu: Type 2b Monotectic System 9
1.4.5 Bi–Cu–Sn: Type 3a Monotectic System 11
1.5 Quaternary Monotectic Al–Bi–Cu–Sn System 11
1.6 Conclusion 15
2 Liquid-liquid Interfacial Tension in Multicomponent Immiscible Al-based
Alloys 19
Walter Hoyer and Ivan G. Kaban
2.1 Introduction 19
2.2 Measurement Technique 21
2.3 Experimental Details 24
2.4 Results 25
2.5 Discussion 30
2.5.1 Composition Dependences of the l–l Interfacial Tension 30
2.5.2 Adsorption at the l–l Interface 32
2.5.3 Temperature Dependence of the l–l Interfacial Tension 34
Phase Transformations in Multicomponent Melts. Edited by D. M. Herlach
Copyright  2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
ISBN: 978-3-527-31994-7
VIII Contents
2.5.4 Wetting Phenomena 34
2.6 Summary 36
3 Monotectic Growth Morphologies and Their Transitions 39
Lorenz Ratke, Anja Mu¨ller, Martin Seifert, and Galina Kasperovich
3.1 Introduction 39
3.2 Experimental Procedures 40
3.2.1 Alloys 40
3.2.2 ARTEMIS Facility 41
3.2.3 Evaluation Procedures 42
3.3 Experimental Results 42
3.3.1 Microstructures 42
3.3.2 Jackson–Hunt Plot 45
3.3.3 Stability Diagrams 46
3.4 Discussion 47
3.4.1 Fibrous Monotectic Growth 47
3.4.2 Transition from Fibers to String of Pearls 48
3.4.3 Origin of Irregular Drops 50
3.5 Outlook 53
4 Thermal Expansion and Surface Tension of Multicomponent Alloys 55
Ju¨rgen Brillo and Ivan Egry
4.1 Introduction 55
4.1.1 General 55
4.1.2 Density and Thermal Expansion 56
4.1.3 Surface Tension 57
4.2 Experimental 58
4.2.1 Levitation 58
4.2.2 Density and Thermal Expansion 59
4.2.3 Surface Tension 59
4.3 Results 60
4.3.1 Density 60
4.3.2 Surface Tension 64
4.4 Conclusion and Summary 69
5 Measurement of the Solid-Liquid Interface Energy in Ternary Alloy
Systems 73
Annemarie Bulla, Emir Subasic, Ralf Berger, Andreas Bu¨hrig-Polaczek, and
Andreas Ludwig
5.1 Introduction 73
5.2 Experimental Procedure 74
5.2.1 The Radial Heat Flow Apparatus 74
5.2.2 Equilibration of the Sample 75
5.2.3 Quenching 75
5.3 Evaluation of the Local Curvature of the Grain Boundary Grooves 75
Contents IX
5.3.1 Preparation of the Sample 75
5.3.2 Geometrical Correction of the Groove Coordinates 76
5.3.3 Determination of the Local Undercooling 77
5.3.4 Determining the Interface Energy 78
5.4 Results and Discussion 79
5.4.1 Al–Cu System with Eutectic Composition 80
5.4.2 Al–Cu–Ag System with Invariant Eutectic Composition 81
5.4.3 Concentration Dependence of σSL 83
5.5 Summary and Conclusions 84
6 Phase Equilibria of Nanoscale Metals and Alloys 87
Gerhard Wilde, Peter Bunzel, Harald Ro¨sner, and Jo¨rg Weissmu¨ller
6.1 Introduction 87
6.2 Phase Stability and Phase Transformations in Nanoscale Systems 88
6.2.1 Single-Phase Material: External Interfaces 88
6.2.2 Binary Nanoalloys: Internal Heterophase Interfaces 97
6.3 Summary 105
Part Two Microscopic and Macroscopic Dynamics 109
7 Melt Structure and Atomic Diffusion in Multicomponent Metallic
Melts 111
Dirk Holland-Moritz, Oliver Heinen, Suresh Mavila Chathoth, Anja Ines
Pommrich, Sebastian Stu¨ber, Thomas Voigtmann, and Andreas Meyer
7.1 Introduction 111
7.2 Experimental Details 113
7.2.1 Quasi elastic Neutron Scattering 113
7.2.2 Elastic Neutron Scattering 115
7.3 Results and Discussion 115
7.3.1 Atomic Dynamics in Liquid Ni 115
7.3.2 Atomic Dynamics in Ni–P-based Glass-forming Alloy Melts 118
7.3.3 Atomic Dynamics in Zr–Ti–Ni–Cu–Be and Zr64Ni36 Alloy Melts 119
7.3.4 The Short-Range Order of Liquid Zr64Ni36 120
7.3.5 Analysis Within Mode Coupling Theory 124
7.4 Conclusions 125
8 Diffusion in Multicomponent Metallic Melts Near the Melting
Temperature 131
Axel Griesche, Michael-Peter Macht, and Gu¨nter Frohberg
8.1 Introduction 131
8.2 Experimental Diffusion Techniques 132
8.2.1 Long-Capillary Method 132
8.2.2 Long-Capillary Method Combined with X-ray Radiography 134
8.3 Influence of Thermodynamic Forces on Diffusion 135
X Contents
8.3.1 Systems with Mixing Tendency: Al–Ni 136
8.3.2 Systems with Demixing Tendency: Pd–Cu–Ni–P 137
9 Phase Behavior and Microscopic Transport Processes in Binary Metallic
Alloys: Computer Simulation Studies 141
Subir K. Das, Ali Kerrache, Ju¨rgen Horbach, and Kurt Binder
9.1 Introduction 141
9.2 Transport Coefficients 143
9.3 A Symmetric LJ Mixture with a Liquid–Liquid Demixing
Transition 144
9.4 Structure, Transport, and Crystallization in Al–Ni Alloys 148
9.5 Summary 154
10 Molecular Dynamics Modeling of Atomic Processes During Crystal
Growth in Metallic Alloy Melts 157
Helmar Teichler and Mohamed Guerdane
10.1 Introduction 157
10.2 Entropy and Free Enthalpy of Zr-rich NixZr1−x Melts from MD
Simulations and Their Application to the Thermodynamics of
Crystallization 158
10.2.1 Survey 158
10.2.2 Results and Their Meaning 158
10.2.2.1 The Method that Works 158
10.2.2.2 Free Enthalpy Results for Zr-rich NixZr1−x Melts 159
10.2.2.3 Zr-rich Part of the (x, T) Phase Diagram 161
10.3 Bridging the Gap between Phase Field Modeling and Molecular
Dynamics Simulations. Dynamics of the Planar
[NixZr1−x]liquid − Zrcrystal Crystallization Front 162
10.3.1 Survey 162
10.3.2 Results and Their Meaning 162
10.3.2.1 MD-Generated Input Parameter for PF Modeling 162
10.3.2.2 Comparison of MD and PF Results for the Concentration Profiles and
Propagation of the Crystallization Front 163
10.4 Entropy and Free Enthalpy in Ternary AlyNi0.4−yZr0.6 Alloy Melts 165
10.4.1 Survey 165
10.4.2 Results and Their Meaning 166
10.4.2.1 The Method: Test of Its Numerical Reliability 166
10.4.2.2 Results for the Entropy Change in the AlyNi0.4−yZr0.6 Melt Series at
1700K 167
10.5 Concluding Remarks 169
11 Computational Optimization of Multicomponent Bernal’s Liquids 171
Helmut Hermann, Antje Elsner, and Valentin Kokotin
11.1 Introduction 171
11.2 Methods 172